This project is directed toward the detection of functional changes in the cardiovascular system associated with the inhalation of anesthetics, fluorocarbons, and brominated compounds as well as energy-related pollutants. The function of isolated, perfused rabbit, rat, and guinea pig hearts will be monitored. Animals may be previously exposed to contaminants followed by excision and perfusion of hearts or the hearts may be exposed acutely in vitro. Myocardial mechanical, electrical, and metabolic activity may be monitored concurrently.